<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="lib/vue.js"></script>
</head>
<body>
  <div id="root">
    <p>{{reverse}}</p>
    <p>{{reverse}}</p>
    <p>{{reverse}}</p>
    <input type="text" v-model="str">
    <p>{{reverse}}</p>
    <p>{{reverse}}</p>
  </div>
</body>
<script>
  new Vue({
    el : '#root',
    data : {
      str : '123456'
    },
    computed : {
      reverse(){
        console.log(1)
        return this.str.split('').reverse().join('');
      },
      tools : {
        get(){
          return this.str.split('').reverse().join('');
        },
        set(v){
          this.str = v.split('').reverse().join('');
        }
      }
    }
  })
</script>
</html>